The present invention relates to an engine efficiency improvement system. More particularly, the present invention relates to efficiently operating a combustion engine with multiple cylinders by deactivating some of the cylinders when the engine is operated under a light load.
The combustion engines have been commercially manufactured for many decades in automobiles, generator sets, compressors, pumps, welders, and even hybrid electric vehicles. One increasingly important concern in the aforementioned engine applications and other engine applications requiring frequent part load power output is maximizing fuel economy. The most common and the least inefficient means of reducing engine power is to reduce the throttle opening. This reduced throttle opening results in a high intake manifold vacuum condition and correspondingly high air pumping losses as each cylinder is trying to draw air through a significantly restricted throttle opening.
The present invention is to deactivate cylinders which are not required to produce the part load power of the engine when the machine, pump, compressor, welder, and automobile, etc. do not require full power.
Cylinder deactivation to reduce power is a well-known practice that goes back to the early years of engine production. In every instance, however, no successful attempt has been made to eliminate the corresponding vibrations which are caused by deactivating some cylinders. The vast differences in pitch, yaw, roll torques are imposed on the engine/machine by the imbalance in power impulse energy between the firing and non-firing cylinders. This effect can be clearly demonstrated by disconnecting one or more spark plug wires on a conventional engine. The shaking is pronounced and objectionable particularly when all but one cylinder are deactivated.
The present invention provides a multiple cylinder combustion engine under a condition of either activating or deactivating any determined number of the cylinders when the engine is operated either under a light load or under a heavy load. In the present invention, when the engine has a light load, some of the cylinders can be deactivated without any additional vibrations, and the rest of cylinders still provide sufficient power to maintain the pre-selected running speed of the engine. In addition, the present invention avoids the pumping losses wherein a throttle plate of the cylinders is widely opened.